Abstract
A fructosyl transferase from garlic, fructan: fructan 6G-fructosyl transferase (6G-FFT), was purified and further characterized. 6G-FFT is a dimer glycoprotein around 120 kDa. Optimal activity was found at pH 6.0 and 25°C, and the enzyme was liable to heat instability and was inhibited by Ag+, Zn2+ and Cu2+. 6G-FFT is a bifunctional enzyme which has transferase and hydrolase activities. Transferase activity did not fit well the Michaelis-Menten kinetics, and its Hill coefficient (2.1±0.3) shows positive cooperativity of multiple binding sites for its substrate in the enzyme. Hydrolase activity shows similar Vmax and Km with transferase activity, which suggested that the substrate concentration must be high enough to offset the expense of hydrolysis and start the fructosyl-transferring activity. This bifunctional enzyme only recognized fructooligosaccharides with over two monosaccharide units as their substrates. These findings will provide a theoretical foundation to regulate the metabolism of fructans to prolong the storage of garlic.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call